This research proposal involves four main components of a continuing study of the tumor host immune relationship: 1. Plasmacytoma tumor specific immunity induced in vitro involves the generation of cytotoxic T cells specific to various tumor Ags. We will develop a series of continuous T cell lines reactive to different tumor antigens, including both MHC restricted and non-restricted lines, and of varying T cell subpopulations. These lines will then be used to characterize the T cell receptors, and the nature of tumor antigens recognized by these T cell populations. 2. Characterization and isolation of NK cells. A series of alloantisera and monoclonal antibodies specific for NK cells will be developed and used to isolate NK cells from a variety of different sources using flow cytometry. The genetic controls of NK reactivity will be further assessed, and congenic lines of mice developed. 3. A series of T cell lymphomas will be characterized extensively for cell surface components with a wide range of hetero-, allo-, and hybridoma derived reagents. Such T cell lines will then be functionally studied as models of specific T cell subpopulations. 4. The series of T cell lymphomas and a variety of other tumors will be extensively analyzed with allo- and hybridoma derived reagents of various anti-H2 specificities, in order to assess the concept that tumor specific antigens may be inappropriately expressed normal MHC coded cell surface molecules.